Everything with a battery should have an off switch
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Re: Everything with a battery should have an off switch
#2Sometimes you don't want that actually. For example if the reason that device has an battery is a RTC (Realtime Clock) and it uses it to keep track of time.
Or with things where battery life is a much smaller issue than forgetting to turn the thing on (e.g. smoke detectors).
Or with things that draw unspeakably low amounts of current and where such switches would be hard to implement (e.g. digital wrist watches).
Other than that: Yes please.
Re: Everything with a battery should have an off switch
#3(Background: I work in product design/new product development, and conceivably might have designed this thing! If any of those were still designed in the Western world. Which they aren't. I have designed some stuff like it, though!)
Oh, great, this debate again! I shall use this post as ammunition next time I am arguing with our stupid design team about why we need an off switch on the stupid product we are designing, because it is a giant pain to live with devices you cannot turn off.
(It is especially fun to put something together for the Very First Time, then realize you can't turn it off... and you need to turn it off because it's the Very First Time this thing has ever existed at all, and it isn't quite right, and you need to fix something. But it can't be turned off, and this is somehow by design.)
(Our design team will never listen. This is because they, one, don't listen to anyone ever; and two, never use the products they design. Oh, sure, there might be a user study or two. But they never actually have to live with or work with the damn things.)
> They never seem to just use the bluetooth module as the sole microcontroller
We actually do this! It works pretty well.
> and also it's not like microcontrollers are expensive these days. with a blobbed-on IC of some 8-bit custom non-programmable thing, they're probably spending like 1-2 cents each
Yeah I wish we could get those prices. But we don't do COB (chip-on-board) and we only use microcontrollers we can get and read datasheets for, so we pay at least 20x that price. Maybe that's why we don't have any clients?
Re: Everything with a battery should have an off switch
#4Examples lying around in my house:
Bathroom scale: lovely it powers up when you tap it, but eats up 2 button cells a year for a few dozen uses a year
Kitchen scales, bit more use, at least once a day but again 2 button cells a year
electronic caliper: Same, eats up 1 button cell a year, just sitting in my toolbox
Strangely enough none of our kids toys with batteries seem to suffer from this problem
How much extra cost does a hard on/off switch add to the bill of materials?
Re: Everything with a battery should have an off switch
#5Sometimes you don't want that actually. For example if the reason that device has an battery is a RTC (Realtime Clock) and it uses it to keep track of time. Or with things where battery life is a much smaller issue than forgetting to turn the thing on (e.g. smoke detectors). Or with things that draw unspeakably low amounts of current and where such switches would be hard to implement (e.g. digital wrist watches). Oth…
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Re: Everything with a battery should have an off switch
#6Obligatory addendum every time foone is posted here: foone goes by they/them pronouns and foone hates HN and all it stands for so please don't bother them with twitter replies just because you saw this thread on here. If you think about following them on twitter because of a cool tech thread, please be aware that they're not a tech novelty account and don't complain when they tweet about politics.
Re: Everything with a battery should have an off switch
#7Examples lying around in my house: Bathroom scale: lovely it powers up when you tap it, but eats up 2 button cells a year for a few dozen uses a year Kitchen scales, bit more use, at least once a day but again 2 button cells a year electronic caliper: Same, eats up 1 button cell a year, just sitting in my toolbox Strangely enough none of our kids toys with batteries seem to suffer from this problem How much extra cos…
>” How much extra cost does a hard on/off switch add to the bill of materials?”
BoM cost is not the whole story; a physical switch can greatly complicate an assembly, and may require hand-soldered wires. In addition to those cost-related factors, external switches are usually quite ugly, and getting them right can be very challenging, so it’s much easier to just omit them.
Re: Everything with a battery should have an off switch
#8Examples lying around in my house: Bathroom scale: lovely it powers up when you tap it, but eats up 2 button cells a year for a few dozen uses a year Kitchen scales, bit more use, at least once a day but again 2 button cells a year electronic caliper: Same, eats up 1 button cell a year, just sitting in my toolbox Strangely enough none of our kids toys with batteries seem to suffer from this problem How much extra cos…
Could you check the voltage on those cells next time you swap?
I've found that seemingly similar devices have very different notions of what constitutes a discharged battery.
I have a remote controlled humidifier and RGB LED - controllers for which use one and two infrared LEDs respectively. Both are powered by CR2025 button cells, which when new have an open circuit voltage of 3.3V and 2.7V once depleted.
The two-LED device considers a 3V cell "dead", while the one-LED will happily work at this voltage.
Re: Everything with a battery should have an off switch
#9Examples lying around in my house: Bathroom scale: lovely it powers up when you tap it, but eats up 2 button cells a year for a few dozen uses a year Kitchen scales, bit more use, at least once a day but again 2 button cells a year electronic caliper: Same, eats up 1 button cell a year, just sitting in my toolbox Strangely enough none of our kids toys with batteries seem to suffer from this problem How much extra cos…
Bathroom scales, kitchen scales and calipers all have versions that work without electricity and aren't much less convenient (if not more convenient since no waiting for electronics to boot up slower than they should or clunky menus)
Re: Everything with a battery should have an off switch
#10…And, one should be able to turn of every led even when powered on… At Ikea I almost bought a nice brushed steel extractor hood, except it had this obnoxiously bright blue led on the front. Why? I know when that thing is on without it drawing my attention constantly.
Same with my Lenovo X13 gen 2, there is a bright white led next to the power button… just why…???